Conventionally, in cleaning industrially manufactured components, or in a cleaning or sterilization and disinfection process in the pharmaceutical and food field, a great amount of chemical agent or gas which involves heavy environmental load has been used. However, addressing global environmental protection, what is currently required is a cleaning or sterilization and disinfection technique with light environmental load. Accordingly, in recent years, ozonated water with light environmental load is gathering attention.
In particular, in removing organic substances including circuit pattern formation-purpose photoresist used in manufacturing precision components such as semiconductors, liquid crystal displays and the like, conventionally, mixture of sulfuric acid and hydrogen peroxide solution, alkaline aqueous solution, or various organic solvents have been used as the cleaning agent. However, for the purpose of environmental protection, attempts to replace them by ozonated water have been made in recent years.
As one example, a method for removing organic substances using ozonated water is proposed in Patent Document 1. The patent proposes to set the water temperature to 45° C. or more for improving the removal effect of organic substances by ozonated water, and to inject carbon dioxide gas for stabilizing the ozonated water concentration.
Further, in order to further improve the removal effect, what is proposed is an ozonated water producing device with which the temperature of ozonated water is set to 70 to 80° C., and the concentration is increased to about 110 mg/L (Patent Documents 2 and 3).
However, even when the high concentration and high temperature ozonated water generated by the conventional devices are used in removing the organic substances (photoresist), the decomposition speed of the resist and the stability of the removal effect are still unsatisfactory. This is because the decomposition reaction of the resist by the ozone molecules is still at the ozone supply rate determining step, not reaching to the reaction determining step.
In order to solve the problem, it is effective to further increase the ozone concentration of the high temperature ozonated water of 70 to 80° C. In order to increase the ozone concentration of the high temperature ozonated water at least twice as great as the conventional concentration, it is essential to cause the ozone mixing concentration of room temperature ozonated water, which is generated prior to heating, to be at least twice as great as that in the conventional techniques (320 mg/L or more to 160 mg/L of that in the conventional techniques).
Further, one of the applicants of the present invention has previously proposed an adsorption scheme concentrating method for concentrating ozone gas, in which property of the ozone molecules adsorbing other substances is used (Patent Document 4).